1. Technical Field
The present invention relates to an optical device and a projector including the optical device.
2. Related Art
A projector which includes a light source, a light modulation device for modulating light emitted from the light source to form image light corresponding to image information, and a projection device for expanding and projecting the image light thus formed on a projection surface such as a screen is known. This type of projector further includes an optical device which has a lens unit for equalizing the amount of light emitted from the light source within a transmission area of the lens unit, a plurality of optical components such as a reflection member for changing the optical path of the light, and an optical component housing for accommodating the plural optical components. The respective optical components are disposed at predetermined positions on an illumination optical axis set inside the optical component housing.
Among these optical components, the reflection member for changing the optical path of the entering light needs to be appropriately positioned with respect to the optical component housing. More specifically, when the reflection member is not disposed at a proper position corresponding to the designed position, the reflection member cannot reflect the entering light toward an appropriate position. In this case, the efficiency of using the light emitted from the light source may be lowered, or the formed image light may be deteriorated. For overcoming this problem, such a structure is known which includes a posture control lever disposed on the back side of a reflection mirror (the side opposite to the light entering side) as the reflection member to control the position of the reflection mirror by operating the lever (for example, see JP-A-2005-202148).
The reflection mirror included in the structure shown in JP-A-2005-202148 is attached to a reflection mirror attachment unit provided on a component receiving member constituting an optical component housing in such a condition as to be urged toward the attachment unit by an urging member. An opening which is formed on the component receiving member and through which optical components are inserted is closed by a cover member which similarly constitutes the optical component housing. In this structure, the position of the reflection mirror is controlled by operating the lever projecting through an opening of the cover member.
According to the projector disclosed in JP-A-2005-202148, the lever projects to the outside of the optical component housing. In this case, the optical component housing containing the reflection mirror becomes large. Particularly when a control board disposed inside the projector to control the overall operation of the projector is provided in such a manner as to cover the optical device having the optical component housing, the increase in the size of the optical device has a significant effect on the overall size of the projector. Thus, an optical device having a reduced size has been demanded.